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(No Model.)

H. G. LUTHER.

MANUEAGTUBE 0E IMITATION STONE EUR JEWELRY,

No. 274,350. Patented Mar. 20, 1883.

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- f UNITED STATES PATENT FFICE.

HENRY C. LUTHER, OF PROVIDENCE, RHODE ISLAND.

MANUFACTURE OF IMiTATION STONE FOR JEWELRY.

SPECIFICATION forming part of Letters Patent No. 274,350, dated March 20, 1883.

Y Application iiled February 8,1883. (No model.)

To all whom it may concern Be it' known that I, HENRY C. LUTHER, of Providence, in the State of Rhode Island, have invented an Improvementin the Manufacture ot' Imitation Stone for Jewelry, of which the following is a specification.

My invention relates to an improvement in the manufacture of glassimitation stone adapted for the settings ofjewelry and millinery ornaments; and it consists in a glass imitation stone having the iins or inequalities formed at the junction of the plunger and die removed by simply grinding the front surface of the stone, the back surface and edge remaining ungroun'd.

Figure l is' au edge elevation of an imitation stone adapted for the settings of jewelry.' Fig. 2 is a top view of the same. Fig. 3 represents the relative position ofthe die and plungerin the ordinary manufacture of such stone. Fig. 4 is au edge elevation of the ,imitation stone as removed from the die shown in Fig. 3. Fig. 5 represents the die and plunger as arranged to manufacture my improved imitation stone. Fig. 6 represents an edge elevation of the imi- 'tation stone as removed from the die shown in Fig. 5.

the stone, as shown in Fig. 4, which necessitates the grinding of the back a., as Well as the front b, in Iinishing the stone for the market. l have been able, however, by reversing the chamber of the die, as shown in Fig. 5, to pinch glass imitation stone, which may be properly finished fort-he market by grinding the sur face at the front b oi' the stone, and thus removing the surplus material, including the fin, by a single grinding operation, Ythe back corner, d, remaining as received from thedie, thus eieeting an important saving '1n the expense of manufacturing such stone.

One great advantage of my improvement is the absolute uniformity of the setting edge or corner d of the stone, which, when ground, is

y liable to variation, according to the skill and and the edge of the imitation st one remaining.

unground and free from the fins and enlargements caused by the Contact ot' the plunger and die, as an improved article of manufacture.

HENRY C. LUTHER.

Witnesses:

D. B. POTTER, S. SGHOLFIELD. 

